The present invention relates to a sound emitter of the type comprising a metal chassis supporting a circuit generating an electrical signal at high frequency and high voltage, which is modiated by a signal at lower frequency that is to be transformed into sound waves, a metal housing fixed detachably to the chassis and forming with the latter a completely closed shielding that encloses the said generating circuit, a metal horn of exponential form which extends into the interior of the metal housing, and of which the output end through an opening in the housing, and a corona-effect transducer containing a tube made of an electrically insulating material resistant to high temperature, which is mounted at the input to the exponential horn and in the bore of which there extends a discharge electrode electrically connected to the output of the said generating circuit and having a tip disposed in proximity to the input end of the horn.
Sound emitters of the above-indicated type, using a modulated corona discharge to cause the ambient air to vibrate and obtain sounds of remarkable purity, are known as "IONOPHONES" and are described, in particular, in French Pat. No. 1,041,790 and the certificates of addition attached thereto of the Applicant.
In known sound emitters of the above type, the tip of the discharge electrode, and the adjacent components, are exposed to a high temperature while in operation, so that these components end up by becoming deteriorated in the long run. In practice it is necessary to replace the corona-effect transducer or at least a part of the latter approximately every two thousand hours. Nevertheless, in known sound emitters of the above type, the replacement of the worn corona-effect transducer by a new transducer, was a relatively complicated operation that had to be done by a specialist, because of the very method of construction of the corona-effect transducer and its method of installation in the emitter. Furthermore, for a given HF power, known transducers have a relatively low efficiency.